Your requirement is not clear.
Are you saying that you want to be able to use your email to read and respond to posts in the forum? All you can do is subscribe (as Lalit has already described) which will send you email notifications, to respond to posts, you'll have to log into the Forum.

No, me neither. I will occasionally use 'subscribe' to a topic that I haven't posted in, if I think that the discussion is interesting, but never to an entire forum. I couldn't be bothered with the email housekeeping!